RxJS-单元测试mergeMap内部Observable

Question

我有以下代码：

  createAsset(asset: Asset): void {
    this._assetsService.uploadFile()
    .pipe(
      mergeMap(_ => this._assetsService.createAsset({
        ...asset,
        extension: 'png'
      })),
      take(1)
    )
    .subscribe(_ => {}, _ => console.error(_));
  }

我想确保只要调用此函数，它就会使用正确的参数调用createAsset。

我确实使用Karma和Jasmine编写了UT：

it('...', async (async () => {
    const assetsService = TestBed.inject(AssetsService);
    const uploadSpy = spyOn(assetsService, 'uploadFile').and.returnValue(of());
    const createSpy = spyOn(assetsService, 'createAsset').and.returnValue(of());

    const extension = 'png';

    const asset = {
      name: 'name',
      extension: null
    };

    component.createAsset(asset);

    await fixture.whenStable();
    expect(uploadSpy).toHaveBeenCalled();
    expect(createSpy).toHaveBeenCalledWith({...asset, extension}); // Error : This is never called
  }));

从未调用mergeMap createSpy的内部对象。 有什么我想念的吗？

Answer 1

 const uploadSpy = spyOn(assetsService, 'uploadFile').and.returnValue(of());

问题在于使用Observable<void>进行模拟时，只需用void以外的任何内容替换它即可解决问题。